High density electrode for electric dual layer capacitor and method of manufacturing the same

ABSTRACT

A high density electrode includes a through type aluminum sheet, a plurality of first hollow protrusion members protruded to one side of the through type aluminum sheet, a plurality of second hollow protrusion members protruded to the other side of the through type aluminum sheet, a first active material sheet bonded to the first surface of the through type aluminum sheet, and a second active material sheet bonded to the second surface of the second surface of the through type aluminum sheet.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2014-0057832, filed on May 14, 2014 and Korean Patent Application No.10-2015-0018624, filed on Feb. 6, 2015 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a high density electrode for anelectric double layer capacitor and a method of manufacturing the sameand, more particularly, to a high density electrode for an electric duallayer capacitor and a method of manufacturing the same, which arecapable of implementing a high density electrode by preventing a loss ofthe surface area of an aluminum sheet that is used in an electrode foran electric dual layer capacitor so that a contact area between thealuminum sheet and an active material sheet is increased when forming aplurality of through holes in the aluminum sheet.

2. Description of the Related Art

An electric double layer capacitor (EDLC) has a less influence on thelifespan although it is repeatedly charged and discharged because itstores electric energy using a physical adsorption phenomenon withreversibility and is being applied to smart phones, hybrid vehicles,electric vehicles, and the energy storage device field applied to solarcell generation. The electric dual layer capacitor has an excellentpower density, but has a low energy density. Accordingly, there is aneed to develop materials for electrodes in order to improve the lowenergy density problem.

Korean Patent No. 1166148 (Patent Document 1) relates to a method ofmanufacturing an aluminum current collector having a three-dimensionalpattern structure using photolithography. In the method of manufacturingthe aluminum current collector disclosed in Patent Document 1, first,after an aluminum foil current collector is washed, it is dried usingnitrogen atmosphere. Thereafter, a photoresist solution is coated on asurface of the dried aluminum foil current collector and then dried andcured so that the photoresist solution is selectively exposed.

Thereafter, the photoresist solution that has not been exposed isselectively removed by scattering a developer on the aluminum currentcollector that has been exposed so that the remaining photoresistsolution is fully cured, thereby forming a pattern on the aluminumcurrent collector. The aluminum foil current collector in which thepattern has been formed is placed between two carbon plates, that is,opposite electrodes, AC power is applied to the aluminum foil currentcollector, and primary etching is performed on the aluminum currentcollector in an electrolyte.

Thereafter, the etched aluminum current collector is dried. Next, thealuminum current collector dried after the primary etching is placedbetween the two carbon plates, that is, opposite electrodes, andsecondary etching is performed on the aluminum current collector.Thereafter, the aluminum foil subjected to the secondary etching iswashed and dried.

As in Patent Document 1, the energy density of a conventional electrodefor an electric dual layer capacitor is improved by forming a pattern,that is, a plurality of through holes, in an aluminum current collectorusing a photolithography process so that a contact area between thealuminum current collector and active materials is increased.

If a plurality of through holes is formed in an aluminum currentcollector that is used in a conventional electrode for an electric duallayer capacitor as in Patent Document 1, however, there is a problem inthat the surface area of the aluminum current collector is lost by anarea that belongs to a total area of the aluminum current collector andthat is occupied by the through holes.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and an object of the presentinvention is to provide a high density electrode for an electric duallayer capacitor and a method of manufacturing the same, which arecapable of implementing a high density electrode by preventing a loss ofthe surface area of an aluminum sheet that is used in an electrode foran electric dual layer capacitor so that a contact area between thealuminum sheet and an active material sheet is increased when forming aplurality of through holes in the aluminum sheet.

In an embodiment, a high density electrode for an electric dual layercapacitor may include a through type aluminum sheet configured to have aplurality of through holes formed in the through type aluminum sheet sothat the through holes are spaced apart from one another, a plurality offirst hollow protrusion members extended from the through type aluminumsheet in such a way as to communicate with the through holes andprotruded to one side of the through type aluminum sheet, a plurality ofsecond hollow protrusion members spaced apart from the plurality offirst hollow protrusion members, extended from the through type aluminumsheet in such a way as to communicate with the through holes, andprotruded to the other side of the through type aluminum sheet, a firstactive material sheet bonded to the first surface of the through typealuminum sheet so that the plurality of first hollow protrusion membersis buried, and a second active material sheet configured to have theplurality of second hollow protrusion members buried in the secondactive material sheet and bonded to a second surface of the through typealuminum sheet so that the second active material sheet is connected tothe first active material sheet through the plurality of first hollowprotrusion members and the plurality of second hollow protrusionmembers.

In an embodiment, a method of manufacturing a high density electrode foran electric dual layer capacitor may include preparing a through typealuminum sheet configured to have a plurality of first hollow protrusionmembers and a plurality of second hollow protrusion members respectivelyformed in the first surface and second surface of the through typealuminum sheet by winding the through type aluminum sheet on a firstroller, preparing a first active material sheet by winding the firstactive material sheet on a second roller, preparing a second activematerial sheet by winding the second active material sheet on a thirdroller, placing the first active material sheet on the first surface ofthe through type aluminum sheet and the second active material sheet onthe second surface of the through type aluminum sheet, transferring thethrough type aluminum sheet and the first active material sheet and thesecond active material sheet to a press unit, bonding the first activematerial sheet and the second active material sheet to the first surfaceand second surface of the through type aluminum sheet, respectively, andsimultaneously pressurizing the first active material sheet and thesecond active material sheet using the press unit so that the firstactive material sheet and the second active material sheet are connectedthrough the plurality of first hollow protrusion members and theplurality of second hollow protrusion members.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the present invention will becomeapparent and more readily appreciated from the following description ofthe exemplary embodiments, taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is a cross-sectional view of a high density electrode which maybe applied to an electric dual layer capacitor according to anembodiment of the present invention;

FIG. 2 is a cross-sectional view illustrating a state before an activematerial sheet is bonded to a through type aluminum sheet of FIG. 1;

FIG. 3 is a rear view of the through type aluminum sheet of FIG. 2 whichis seen from the other side;

FIG. 4 is a table illustrating various embodiments of first hollowprotrusion members illustrated in FIG. 2;

FIG. 5 is a process flowchart illustrating a method of manufacturing thehigh density electrode, which may be applied to an electric dual layercapacitor in accordance with an embodiment of the present invention;

FIG. 6 is a table illustrating the characteristics of activated carbonthat is used to manufacture the high density electrode, which may beapplied to an electric dual layer capacitor in accordance with anembodiment of the present invention; and

FIG. 7 is a diagram schematically illustrating the configuration of anapparatus for manufacturing the high density electrode, which may beapplied to an electric dual layer capacitor in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. Exemplary embodiments are described below to explain thepresent invention by referring to the figures.

Hereinafter, a high density electrode for an electric dual layercapacitor and a method of manufacturing the same according to someembodiments of the present invention are described.

As illustrated in FIGS. 1 and 2, the high density electrode for anelectric dual layer capacitor in accordance with an embodiment of thepresent invention may include a through type aluminum sheet 10, a firstactive material sheet 20, and a second active material sheet 30.

The through type aluminum sheet 10 has a plurality of through holes 11 aand 12 a spaced apart from one another and formed therein and includes aplurality of first hollow protrusion members 11 and a plurality ofsecond hollow protrusion members 12. The plurality of first hollowprotrusion members 11 is extended from the through type aluminum sheet10 in such a way as to respectively communicate with the plurality ofthrough holes 11 a and is protruded to one side of the through typealuminum sheet 10. The plurality of second hollow protrusion members 12is spaced apart from the plurality of first hollow protrusion members11. Furthermore, the plurality of second hollow protrusion members 12 isextended from the through type aluminum sheet 10 in such a way as torespectively communicate with the through holes 12 a and is protruded tothe other side of the through type aluminum sheet 10. The first activematerial sheet 20 is bonded to the first surface 10 a of the throughtype aluminum sheet 10 so that the plurality of first hollow protrusionmembers 11 is buried. The second active material sheet 30 is bonded tothe second surface 10 b of the through type aluminum sheet 10 so thatthe plurality of second hollow protrusion members 12 is buried and thesecond active material sheet 30 is connected to the first activematerial sheet 20 through the plurality of first hollow protrusionmembers 11 and the plurality of second hollow protrusion members 12.

The configuration of the high density electrode for an electric duallayer capacitor in accordance with an embodiment of the presentinvention is described in more detail below.

As illustrated in FIGS. 1 to 3, the through type aluminum sheet 10includes the plurality of through holes 11 a and 12 a spaced apart fromone another. The first surface 10 a and second surface 10 b of thethrough type aluminum sheet 10 are formed to be penetrated. Each of thediameters D1 and D3 of the respective holes 11 a and 12 a may be 50 to100 μm. The through type aluminum sheet 10 in which the plurality ofthrough holes 11 a and 12 a is formed may have a thickness T1 of 10 to50 μm. The through type aluminum sheet 10 improves a specific resistancecharacteristic using purity of 99.20 to 99.99%, thereby improving theelectrical properties of the high density electrode applied to anelectric dual layer capacitor according to an embodiment of the presentinvention. In this case, FIG. 1 is an enlarged sectional view of aportion “Aa” illustrated in FIG. 7, and the through type aluminum sheet10 of FIG. 2 is a cross-sectional view of line “A-A” illustrated in FIG.3.

As illustrated in FIGS. 2 and 3, the plurality of through holes 11 a and12 a is formed in the through type aluminum sheet 10 by perforating thethrough type aluminum sheet 10 using one of a cylindrical pillar member(not illustrated), an elliptical pillar member (not illustrated), and asquare pillar member (not illustrated) each having a pointed tip, suchas a needle or a drill, by applying pressure on the part of the firstsurface 10 a or the second surface 10 b. The plurality of first hollowprotrusion members 11 and the plurality of second hollow protrusionmembers 12 are extended from the through type aluminum sheet 10 andprotruded so that they respectively communicate with the plurality ofthrough holes 11 a and 12 a. As illustrated in FIG. 4, each of theplurality of through holes 11 a and 12 a may have one of a cylindricalshape, an oval, and a square shape and may be formed as one of thecylindrical pillar member, the elliptical pillar member, and the squarepillar member. FIG. 4 is a table illustrating various embodiments of thefirst hollow protrusion member 11. The second hollow protrusion member12 is applied like the first hollow protrusion members 11 of FIG. 4, andthus a description and drawings of various embodiments of the secondhollow protrusion members 12 are omitted.

For example, the plurality of first hollow protrusion members 11 mayinclude the plurality of through holes 11 a formed in the through typealuminum sheet 10 by perforating one of the cylindrical pillar member,the elliptical pillar member, and the square pillar member having apoint end in the direction toward the first surface 10 a of the throughtype aluminum sheet 10 by applying pressure. The plurality of firsthollow protrusion members 11 is extended from the through holes 11 a bythe softness of the through type aluminum sheet 10 and protruded to oneside of the through type aluminum sheet 10. In this case, the throughhole 11 a may have one of a cylindrical shape, an oval, and a squareshape because it is formed of one of the cylindrical pillar member, theelliptical pillar member, and the square pillar member, as illustratedin FIG. 4.

Each of the plurality of through holes 11 a may have one of acylindrical shape, an oval, and a square shape because it is formed ofthe cylindrical pillar member, the elliptical pillar member, and thesquare pillar member, as illustrated in FIG. 4. For example, if thecylindrical pillar member is used, each of the plurality of throughholes 11 a may have a cylindrical shape as in a column Y1. If theelliptical pillar member is used, each of the plurality of through holes11 a may have an oval as in a column Y3. If the square pillar member isused, each of the plurality of through holes 11 a may have a squareshape as in a column Y2. The first hollow protrusion members 11illustrated in a row X3 are perspective views of the first hollowprotrusion members 11 illustrated in a row X2.

The plurality of through holes 12 a of the plurality of second hollowprotrusion members 12 is formed in the through type aluminum sheet 10 byperforating the through type aluminum sheet 10 in the direction towardthe second surface 10 b of the through type aluminum sheet 10 byapplying pressure using one of the cylindrical pillar member, theelliptical pillar member, and the square pillar member each having apointed tip. The plurality of second hollow protrusion members 12 isextended from the through holes 11 a by the softness of the through typealuminum sheet 10 and protruded to the other side of the through typealuminum sheet 10. In this case, like the plurality of through holes 11a of FIG. 4, each of the plurality of through holes 12 a has one of acylindrical shape, an oval, and a square shape because it is formed ofone of the cylindrical pillar member, the elliptical pillar member, andthe square pillar member, as illustrated in FIG. 4.

The plurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 include one or more extruded burrmembers 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d because they aremade of one of the cylindrical pillar member, the elliptical pillarmember, and the square pillar member each having a pointed tip. Forexample, as illustrated in FIG. 3, the first hollow protrusion member 11and the second hollow protrusion member 12 may include respectiveextruded burr members 11 b and 12 b or may have two or more extrudedburr members 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d. That is, asingle through type aluminum sheet 10 may include the first hollowprotrusion member 11 and the second hollow protrusion member 12 thatinclude respective extruded burr members 11 b and 12 b or include thetwo or more extruded burr members 11 b, 11 c, and 11 d and 12 b, 12 c,and 12 d, respectively. As in the first hollow protrusion members 11 ofFIG. 4, the first hollow protrusion member 11 may include four extrudedburr members 11 b, 11 c, 11 d, and 11 e if the through hole 11 a isformed to have a square shape or an oval as in the column Y3 or thecolumn Y3. The same principle applied to the first hollow protrusionmembers 11 may be applied to the second hollow protrusion members 12. Inthe table of FIG. 4, the row X1 illustrates an embodiment in which twoextruded burr members 11 b and 11 c have been formed in the first hollowprotrusion member 11. The row X2 illustrates an embodiment in whichthree or four extruded burr members 11 b, 11 c, 11 d, and 11 e have beenformed in the first hollow protrusion member 11. The row X3 is aperspective view of the first hollow protrusion member 11 illustrated inthe row X1. Furthermore, FIG. 1 is a cross-sectional view of a highdensity electrode of an electric dual layer capacitor formed the firsthollow protrusion members 11 and the second hollow protrusion members 12in which the two extruded burr members 11 b, 11 c, and 12 b, 12 cillustrated in the row X1 and column Y1 of FIG. 4 have been formed.

The one or more extruded burr members 11 b, 11 c, and 11 d and 12 b, 12c, and 12 d are extended from the through holes 11 a and 12 a and areintegrally formed in the through type aluminum sheet 10 so that they arespaced apart from one another. The one or more extruded burr members 11b, 11 c, and 11 d and 12 b, 12 c, and 12 d have respective heights T2and T3 of 2 to 70 μm. For example, as illustrated in FIGS. 2 and 4, theheights T2 and T3 of the extruded burr members 11 b and 12 b are thehighest heights from the first surface 10 a of the through type aluminumsheet 10 or the second surface 10 b. The plurality of extruded burrmembers 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d has beenillustrated as having a height of 2 μm or more from the first surface 10a of the through type aluminum sheet 10 or the second surface 10 b inthe state in which they have been separated. Since the plurality offirst hollow protrusion members 11 and the plurality of second hollowprotrusion members 12 are formed to have the one or more extruded burrmembers 11 b, 11 c, and 11 d and 12 b, 12 c, and 12 d as describedabove, the surface area of the through type aluminum sheet 10 can befurther increased, thereby being capable of implementing an electrodewith a high density. For example, if the first hollow protrusion member11 and the second hollow protrusion member 12 are formed of cylindricalpillar members, the cylindrical through holes 11 a and 12 a havinguniform diameters D1 and D3 may be formed in the first hollow protrusionmember 11 and the second hollow protrusion member 12, or the extrudedburr members 11 b and 12 b may be formed so that one side or the otherside of the first hollow protrusion member 11 and the second hollowprotrusion member 12 has an inside diameter D2, D4 equal to or smallerthan the diameter D1, D3. Accordingly, an electrode with a high densitycan be implemented because the surface area of the through type aluminumsheet 10 is further increased.

The first active material sheet 20 and the second active material sheet30 are simultaneously pressurized and bonded to the first surface 10 aand second surface 10 b of the through type aluminum sheet 10 byrepeating a roll press method twice or more so that they are connectedthrough the plurality of first hollow protrusion members 11 and theplurality of second hollow protrusion members 12 as illustrated in FIGS.1 and 2. If the roll press method is repeatedly performed twice or more,the thicknesses T4 and T5 of the first active material sheet 20 and thesecond active material sheet 30 pressurized by the roll press methodthat is finally performed are 2 to 30% smaller than the thicknesses (notillustrated) of the first active material sheet 20 and the second activematerial sheet 30 pressurized by the roll press method that is firstperformed.

As described above, the first active material sheet 20 and the secondactive material sheet 30 are simultaneously pressurized and bonded tothe through type aluminum sheet 10 by repeating the roll press methodtwice or more. Accordingly, external appearances of the plurality offirst hollow protrusion members 11 and the plurality of second hollowprotrusion members 12 can be prevented from being changed or damage tothe through holes 11 a and 12 a, such as that the through holes 11 a and12 a are clogged, can be prevented due to applied pressure for bondingthe first active material sheet 20 and the second active material sheet30 together, and an equivalent series resistance characteristic can beprevented from being deteriorated, thereby being capable of implementingan electrode with a high density.

For example, the high density electrode for an electric dual layercapacitor in accordance with an embodiment of the present invention maybe formed by repeating a roll press method twice or more using a pressunit 140 illustrated in FIG. 7.

In the roll press method that is first performed, the first activematerial sheet 20 and the second active material sheet 30 arerespectively bonded to the first surface 10 a and second surface 10 b ofthe through type aluminum sheet 10 by applying pressure lower than thatused in the roll press method that is finally performed. That is, sincethe first active material sheet 20 and the second active material sheet30 are bonded to the through type aluminum sheet 10 with low pressure, achange in external appearances of the plurality of first hollowprotrusion members 11 and the plurality of second hollow protrusionmembers 12 attributable to the pressure can be prevented. As describedabove, in the roll press method that is first performed, the firstactive material sheet 20 and the second active material sheet 30 arepartially filled in the first hollow protrusion members 11 or the secondhollow protrusion members 12. As a result, a change in externalappearances of the first hollow protrusion members 11 or the secondhollow protrusion members 12, which may occur because pressure higherthan the pressure used in the roll press method that is first performedis applied to the first hollow protrusion members 11 or the secondhollow protrusion members 12, can be prevented.

If the roll press method that is second performed is a roll press methodthat is finally performed, in the roll press method that is finallyperformed, the first active material sheet 20 and the second activematerial sheet 30 are bonded to the first surface 10 a and secondsurface 10 b of the through type aluminum sheet 10 by applying pressurehigher than that used in the roll press method that is first performed.In the roll press method that is finally performed, although pressurehigher than that used in the roll press method that is first performedis applied, external appearances of the first hollow protrusion members11 or the second hollow protrusion members 12 can be prevented frombeing changed because the first active material sheet 20 and the secondactive material sheet 30 have been partially filled in the first hollowprotrusion members 11 or the second hollow protrusion members 12 to someextent. In the roll press method that is finally performed, the firstactive material sheet 20 and the second active material sheet 30 aresimultaneously pressurized by applying pressure higher than that used inthe roll press method that is first performed. Accordingly, the firstactive material sheet 20 and the second active material sheet 30 arefilled in the plurality of through holes 11 a and 12 a in the state inwhich they have been filled in the plurality of first hollow protrusionmembers 11 and the plurality of second hollow protrusion members 12 andare thus connected.

By the roll press method that is finally performed, the first activematerial sheet 20 and the second active material sheet 30 are filled inthe plurality of through holes 11 a and 12 a in the state in which theyhave been filled in the plurality of first hollow protrusion members 11and the plurality of second hollow protrusion members 12 and bonded tothe inner circumference surfaces or outer circumference surfaces of theplurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12. Accordingly, a high density can beachieved because a ratio of weight per unit volume is increased, and thedeterioration of an equivalent series resistance characteristic can beprevented because a contact area between the through type aluminum sheet10 and the first active material sheet 20 and the second active materialsheet 30 is increased. The first active material sheet 20 and the secondactive material sheet 30 are made of the same active materials andpressurized so that the thicknesses T4 and T5 thereof are reduced by 2to 30%. Accordingly, an electrode with a high density can bemanufactured using a physical method, and each of the thicknesses T4 andT5 is 100 to 500 μm. In this case, activated carbon may be used as theactive materials, and activated carbon may have an average particlediameter of about 1 to 10 μm and a specific surface area of 1200 to 2200m²/g.

A method of manufacturing the high density electrode for an electricdual layer capacitor in accordance with an embodiment of the presentinvention is described below with reference to the accompanyingdrawings.

In the method of manufacturing the high density electrode for anelectric dual layer capacitor in accordance with an embodiment of thepresent invention, as illustrated in FIGS. 5 and 7, first, the throughtype aluminum sheet 10 in which the plurality of first hollow protrusionmembers 11 and the plurality of second hollow protrusion members 12 havebeen respectively formed in the first surface 10 a and second surface 10b of the through type aluminum sheet 10 is prepared by winding thethrough type aluminum sheet 10 on a first roller 110 at step S10.Furthermore, the first active material sheet 20 is prepared by windingthe first active material sheet 20 on a second roller 120 at step S20,and the second active material sheet 30 is prepared by winding thesecond active material sheet 30 on a third roller 130 at step S30. Whenthe first roller 110, the second roller 120, and the third roller 130are prepared, the first active material sheet 20 is placed on the firstsurface 10 a of the through type aluminum sheet 10, the second activematerial sheet 30 is placed on the second surface 10 b of the throughtype aluminum sheet 10, and the through type aluminum sheet 10, thefirst active material sheet 20, and the second active material sheet 30are transferred to the press unit 140 at step S40. When the through typealuminum sheet 10, the first active material sheet 20, and the secondactive material sheet 30 are transferred to the press unit 140, thefirst active material sheet 20 and the second active material sheet 30are simultaneously pressurized by the press unit 140 so that they arerespectively bonded to the first surface 10 a and second surface 10 b ofthe through type aluminum sheet 10 and they are connected through theplurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 at step S50. Thereafter, the resultsare dried through a known dry process, thereby manufacturing the highdensity electrode for an electric dual layer capacitor in accordancewith an embodiment of the present invention.

At step S10 of preparing the through type aluminum sheet 10 by windingit on the first roller 110, the plurality of through holes 11 a and 12 ais formed in the through type aluminum sheet 10 by perforating thethrough type aluminum sheet 10 using one of the cylindrical pillarmember (not illustrated), the elliptical pillar member (notillustrated), and the square pillar member (not illustrated) each havinga pointed tip, such as a needle or a drill, by applying pressure to thefirst surface 10 a or the second surface 10 b of the through typealuminum sheet 10. Furthermore, the plurality of first hollow protrusionmembers 11 or the plurality of second hollow protrusion members 12 isintegrally formed in the through type aluminum sheet 10 so that they areextended from the through type aluminum sheet 10 and protruded in such away as to communicate with the plurality of through holes 11 a and 12 a.

The plurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 formed in the through type aluminumsheet 10 are protruded to one side or the other side of the through typealuminum sheet 10, that is, in a first direction or a second direction.The first direction is a direction toward the first surface 10 a of thethrough type aluminum sheet 10. The second direction is opposite thefirst direction and is a direction toward the second surface 10 b of thethrough type aluminum sheet 10.

At step S20 of preparing the first active material sheet 20 by windingit on the second roller 120 and step S30 of preparing the second activematerial sheet 30 by winding it on the third roller 130, the firstactive material sheet 20 and the second active material sheet 30 aremade of the same active materials. The active materials may include anelectrode substance of 60 to 80 wt % and a viscosity control substanceof 20 to 40 wt % and may have viscosity of 5000 to 10000 cps (centiPoise). The first active material sheet 20 and the second activematerial sheet 30 having some degree of viscosity as described above aretransferred and bonded to the through type aluminum sheet 10, therebybeing capable of improving adhesive strength between the first activematerial sheet 20 and the second active material sheet 30. In this case,the electrode substance may include activated carbon of 85 to 95 wt %, aconductive agent of 3 to 8 wt %, and a binder of 2 to 7 wt %. Theviscosity control substance may include alcohol of 30 to 60 wt % andpure water of 40 to 70 wt %. Activated carbon is manufactured byperforming activation processing on carbon particle powder fabricatedusing a known aqueous solution method. The activation processing isperformed by mixing the carbon particle powder and mixed alkali in a wt% ratio of 1:2 to 3, drying the mixture, and performing annealing on themixture in a tube furnace under a nitrogen atmosphere in a temperatureof 600 to 1000° C. The mixed alkali is mixed so that a wt % ratio ofNaOH and KOH is 1:9 to 12.

A method of manufacturing activated carbon is described in detail below.First, carbon particle powder is fabricated using a known aqueoussolution method. Known raw materials may be used as the carbon particlepowder. Pitch coke, coconut peels, or a bio substance may be used as theraw materials. Potato starch or pine nuts or corn may be used as the biosubstance. After the carbon particle powder is fabricated, activationprocessing is performed on the carbon particle powder. In the activationprocessing, first, the carbon particle powder is immersed in a mixedalkali solution for 30 minutes to 2 hours, and the carbon particlepowder and mixed alkali are mixed by agitating them for 10 to 15 hours.

After the carbon particle powder is mixed with mixed alkali, the mixtureis filtered using a known filter and dried in vacuum in a temperature of100 to 130° C. for 10 to 15 hours. Thereafter, the mixture is activatedby performing annealing in a tube furnace under a nitrogen atmosphere ina temperature of 600 to 1000° C. for 30 minutes to 1½ hours. When theactivation is completed, the carbon particle powder mixed with mixedalkali is repeatedly washed using distilled water once to 10 times anddried, thereby fabricating activated carbon.

When fabricating activated carbon, mixed alkali including NaOH and KOHforms pores having two types of sizes according to NaOH and KOH inactivated carbon. That is, K ions and Na ions form pores of differentsizes in activated carbon because they have different sizes anddifferent activation operations. For example, K ions may form pores thatare narrower and deeper than pores formed by the activation of Na. Naions may form pores that are wider and smaller than pores formed by theactivation of K ions.

As illustrated in FIG. 6, the specific surface area of activated carbonwas increased in experiments in which a wt % ratio of carbide and mixedalkali was changed to 1:3, 1:2.6, 1:2.3, and 1:2 in the state in which awt % ratio of NaOH and KOH was fixed to 1:9. If a wt % ratio of KOH isincreased in mixed alkali as in those experimental embodiments, thespecific surface area of activated carbon is increased from 1200 m²/g to2200 m²/g as illustrated in FIG. 6, thereby enabling activated carbonhaving an average particle diameter of 1 to 10 μm to be used. That is,the specific surface area of activated carbon is increased althoughactivated carbon has a small average particle diameter. Accordingly, ahigh density electrode can be implemented by increasing the capacity ofactivated carbon per volume.

Metal impurities that remain in activated carbon was reduced by changinga wt % ratio of carbide and mixed alkali into 1:3, 1:2.6, 1:2.3, or 1:2in the state in which the wt % ratio of NaOH and KOH was fixed to 1:9,as illustrated in FIG. 6. For example, there is an advantage in that themetal impurities were improved by the pores formed by Na ions whenwashing activated carbon, as illustrated in FIG. 6. In this case, themetal impurities that remain after washing activated carbon may includeNi and K.

As described above, the specific surface area is increased, but themetal impurities are reduced depending on a ratio of carbide and mixedalkali. However, if an optimal ratio of carbide and mixed alkali isselected depending on the purpose of use of activated carbon, capacityper volume can be increased and the amount of the metal impurities thatremain can be reduced.

At step S50 of simultaneously pressurizing the first active materialsheet 20 and the second active material sheet 30 using the press unit140, as illustrated in FIG. 7, first, when the first active materialsheet 20, the second active material sheet 30, and the through typealuminum sheet 10 are transferred to a pair of first press rollers 141,the first active material sheet 20 and the second active material sheet30 are primarily pressurized using the pair of first press rollers 141with first pressure at the same time so that the first active materialsheet 20 and the second active material sheet 30 are respectively bondedto the first surface 10 a and second surface 10 b of the through typealuminum sheet 10 at step S51.

When the through type aluminum sheet 10 onto which the first activematerial sheet 20 and the second active material sheet 30 have primarilypressurized is transferred to a pair of second press rollers 142, thefirst active material sheet 20 and the second active material sheet 30that have been primarily pressurized are secondarily pressurized usingthe pair of second press rollers 142 with second pressure higher thanthe first pressure at the same time so that the first active materialsheet 20 and the second active material sheet 30 are connected throughthe plurality of first hollow protrusion members 11 and the plurality ofsecond hollow protrusion members 12 at step S52. In this case, thepressurization is performed so that the thicknesses T4 and T5 of thefirst active material sheet 20 and the second active material sheet 30bonded to the first surface 10 a and second surface 10 b of the throughtype aluminum sheet 10 by the second pressure are 2 to 30% smaller thanthe thicknesses (not illustrated) of the first active material sheet 20and the second active material sheet 30 bonded to the first surface 10 aand second surface 10 b of the through type aluminum sheet 10 by thefirst pressure.

As illustrated in FIG. 7, the first pressure may be set by an intervalM1, that is, a separation distance between the pair of first pressrollers 141, and the second pressure may be set by an interval M2, thatis, a separation distance between the pair of second press rollers 142.That is, the pair of first press rollers 141 is spaced apart from eachother at the interval M1 so that the first pressure is applied to thefirst active material sheet 20 and the second active material sheet 30,the first active material sheet 20 is formed to a thickness T6, and thesecond active material sheet 30 is formed to a thickness T7.Furthermore, the pair of second press rollers 142 is spaced apart fromeach other at the interval M2 so that the second pressure is applied tothe first active material sheet 20 and the second active material sheet30, the first active material sheet 20 is formed to the thickness T4,and the second active material sheet 30 is formed to the thickness T5.Accordingly, the thicknesses T4 and T5 of the first active materialsheet 20 and the second active material sheet 30 become 2 to 30% smallerthan thicknesses T6 and T7. In this case, the thicknesses T6 and T7 arethe same, and the thicknesses T4 and T5 are also the same.

The thicknesses T4 and T5 of the first active material sheet 20 and thesecond active material sheet 30 that have been secondarily pressurizedby the second pressure so that they become 2 to 30% smaller than thethickness T6 and T7 of the first active material sheet 20 and the secondactive material sheet 30 that have been primarily pressurized by thefirst pressure are generated due to a difference M3+M4 between theinterval M1 between the pair of first press rollers 141 and the intervalM2 between the pair of second press rollers 142. That is, the firstpressure and the second pressure are set by the interval M1 between thepair of first press rollers 141 of the press unit 140 and the intervalM2 between the pair of second press rollers 142 of the press unit 140. Adifference between the first pressure and the second pressure isgenerated due to the difference M3+M4 between the interval M1 betweenthe pair of first press rollers 141 and the interval M2 between the pairof second press rollers 142. For example, if the interval M1 is set tobe identical with an interval M2+M3+M4, the thicknesses T4 and T5 of thefirst active material sheet 20 and the second active material sheet 30may become 2 to 30% smaller than the thicknesses T6 and T7, therebyeasily implementing an electrode with a high density. In this case, theintervals M1 and M2 are respectively indicative of the interval betweenthe pair of first press rollers 141 spaced apart from each other or theinterval between the pair of second press rollers 142 spaced apart fromeach other.

When the first active material sheet 20 and the second active materialsheet 30 are simultaneously pressurized to have the thicknesses T4 andT5 reduced by 2 to 30% and thus connected through the plurality of firsthollow protrusion members 11 and the plurality of second hollowprotrusion members 12, the first active material sheet 20 and the secondactive material sheet 30 are dried using a known dry process, so thehigh density electrode for an electric dual layer capacitor inaccordance with an embodiment of the present invention is fabricated.

In order to further improve adhesive strength between the through typealuminum sheet 10 and the first active material sheet 20 and the secondactive material sheet 30, conductive adhesives are used in the highdensity electrode for an electric dual layer capacitor in accordancewith an embodiment of the present invention. Known materials may be usedas the conductive adhesives. After the conductive adhesives are coatedon the first surface 10 a or second surface 10 b of the through typealuminum sheet 10 in the spray state, the first active material sheet 20and the second active material sheet 30 are pressurized by the pair ofpress rollers 140 so that the first active material sheet 20 and thesecond active material sheet 30 are more firmly bonded to the throughtype aluminum sheet 10 through the conductive adhesives. Accordingly,the high density electrode for an electric dual layer capacitor inaccordance with an embodiment of the present invention is fabricated.

As described above, the high density electrode for an electric duallayer capacitor and the method of manufacturing the same according tothe embodiments of the present invention can implement a high densityelectrode by preventing a loss of the surface area of an aluminum sheetthat is used in an electrode for an electric dual layer capacitor sothat a contact area between the aluminum sheet and the active materialsheet is increased when forming the plurality of through holes in thealuminum sheet.

The high density electrode for an electric dual layer capacitor and themethod of manufacturing the same according to the embodiments of thepresent invention may be applied to the manufacturing industry field forelectric dual layer capacitors.

Although a few exemplary embodiments of the present invention have beenshown and described, the present invention is not limited to thedescribed exemplary embodiments. Instead, it would be appreciated bythose skilled in the art that changes may be made to these exemplaryembodiments without departing from the principles and spirit of theinvention, the scope of which is defined by the claims and theirequivalents.

What is claimed is:
 1. A high density electrode for an electric duallayer capacitor, comprising: a through type aluminum sheet configured tohave a plurality of through holes formed in the through type aluminumsheet so that the through holes are spaced apart from one another; aplurality of first hollow protrusion members extended from the throughtype aluminum sheet in such a way as to communicate with the throughholes and protruded to a first side of the through type aluminum sheet;a plurality of second hollow protrusion members spaced apart from theplurality of first hollow protrusion members, extended from the throughtype aluminum sheet in such a way as to communicate with the throughholes, and protruded to a second side of the through type aluminumsheet; a first active material sheet bonded to a first surface of thethrough type aluminum sheet so that the plurality of first hollowprotrusion members is buried; and a second active material sheetconfigured to have the plurality of second hollow protrusion membersburied in the second active material sheet and bonded to a secondsurface of the through type aluminum sheet so that the second activematerial sheet is connected to the first active material sheet throughthe plurality of first hollow protrusion members and the plurality ofsecond hollow protrusion members.
 2. The high density electrode of claim1, wherein: the plurality of through holes spaced apart from one anotheris formed in the through type aluminum sheet, the first surface andsecond surface of the through type aluminum sheet penetrate theplurality of through holes, and each of the plurality of through holeshas a diameter of 50 to 100 μm.
 3. The high density electrode of claim1, wherein the through type aluminum sheet has a thickness of 10 to 50μm.
 4. The high density electrode of claim 1, wherein: each of theplurality of first hollow protrusion members and the plurality of secondhollow protrusion members is formed by perforating the through typealuminum sheet by applying pressure on the first side or second side ofthe through type aluminum sheet using one of a cylindrical pillarmember, an elliptical pillar member, and a square pillar member eachhaving a pointed tip so that the plurality of through holes is formed inthe through type aluminum sheet, the plurality of first hollowprotrusion members and the plurality of second hollow protrusion membersare extended and protruded from the through type aluminum sheet in sucha way as to respectively communicate with the plurality of throughholes, and each of the through holes has one of a cylindrical shape, anoval, and a square shape by one of the cylindrical pillar member, theelliptical pillar member, and the square pillar member.
 5. The highdensity electrode of claim 1, wherein each of the plurality of firsthollow protrusion members and the plurality of second hollow protrusionmembers comprises one or more extruded burr members formed by one of acylindrical pillar member, an elliptical pillar member, and a squarepillar member each having a pointed tip.
 6. The high density electrodeof claim 5, wherein: the one or more extruded burr members are spacedapart from one another and integrally formed in the through typealuminum sheet so that the extruded burr members are extended from thethrough hole, and each of the one or more extruded burr members has aheight of 2 to 70 μm.
 7. The high density electrode of claim 1, wherein:the first active material sheet and the second active material sheet aresimultaneously pressurized and bonded to the first surface and secondside of the through type aluminum sheet by repeating a roll press methodtwice or more so that the first active material sheet and the secondactive material sheet are connected through the plurality of firsthollow protrusion members and the plurality of second hollow protrusionmembers, and if the roll press method is repeatedly performed twice ormore, each of a thickness of the first active material sheet and athickness of the second active material sheet pressurized by a rollpress method that is finally performed is 2 to 30% smaller than each ofa thickness of the first active material sheet and a thickness of thesecond active material sheet pressurized by a roll press method that isfirst performed.
 8. The high density electrode of claim 1, wherein: thefirst active material sheet and the second active material sheet aremade of identical active materials, each of the first active materialsheet and the second active material sheet has a thickness of 100 to 500μm, the active materials comprise activated carbon, and the activatedcarbon has an average particle diameter of 3 to 5 μm and a specificsurface area of 1200 to 2200 m²/g.
 9. A method of manufacturing a highdensity electrode for an electric dual layer capacitor, the methodcomprising: preparing a through type aluminum sheet configured to have aplurality of first hollow protrusion members and a plurality of secondhollow protrusion members respectively formed in a first surface andsecond surface of the through type aluminum sheet by winding the throughtype aluminum sheet on a first roller; preparing a first active materialsheet by winding the first active material sheet on a second roller;preparing a second active material sheet by winding the second activematerial sheet on a third roller; placing the first active materialsheet on the first surface of the through type aluminum sheet and thesecond active material sheet on the second surface of the through typealuminum sheet and transferring the through type aluminum sheet and thefirst active material sheet and the second active material sheet to apress unit; and bonding the first active material sheet and the secondactive material sheet to the first surface and second surface of thethrough type aluminum sheet, respectively, and simultaneouslypressurizing the first active material sheet and the second activematerial sheet using the press unit so that the first active materialsheet and the second active material sheet are connected through theplurality of first hollow protrusion members and the plurality of secondhollow protrusion members.
 10. The method of claim 9, wherein preparingthe through type aluminum sheet comprises: forming a plurality ofthrough holes in the through type aluminum sheet by perforating thethrough type aluminum sheet by applying pressure in the first surface orthe second surface using one of a cylindrical pillar member, anelliptical pillar member, and a square pillar member each having apointed tip, and integrally forming the plurality of first hollowprotrusion members or the plurality of second hollow protrusion membersso that the plurality of first hollow protrusion members or theplurality of second hollow protrusion members are extended and protrudedfrom the through type aluminum sheet in such a way as to respectivelycommunicate with the plurality of through holes.
 11. The method of claim10, wherein each of the plurality of first hollow protrusion members andthe plurality of second hollow protrusion members is protruded to afirst side or second side of the through type aluminum sheet.
 12. Themethod of claim 9, wherein in preparing the first active material sheetand preparing the second active material sheet, the first activematerial sheet and the second active material sheet are made ofidentical active materials, and the active materials comprise anelectrode substance of 60 to 80 wt % and a viscosity control substanceof 20 to 40 wt % and have viscosity of 5000 to 10000 cps (centi Poise).13. The method of claim 12, wherein: the electrode substance comprisesactivated carbon of 85 to 95 wt %, a conductive agent of 3 to 8 wt %,and a binder of 2 to 7 wt %, the activated carbon is fabricated byperforming activation processing on carbon particle powder fabricatedusing an aqueous solution method, the activation processing is performedby mixing the carbon particle powder and mixed alkali in a wt % ratio of1:2 to 3, drying the mixture, and annealing the dried mixture in a tubefurnace under a nitrogen atmosphere in a temperature of 600 to 1000° C.,and the mixed alkali is mixed so that a wt % ratio of NaOH and KOH is1:9 to
 12. 14. The method of claim 12, wherein the viscosity controlsubstance comprises alcohol of 30 to 60 wt % and pure water of 40 to 70wt %.
 15. The method of claim 9, wherein simultaneously pressurizing thefirst active material sheet and the second active material sheet usingthe press unit comprises: primarily pressurizing the first activematerial sheet and the second active material sheet with first pressureusing a pair of first press rollers so that the first active materialsheet and the second active material sheet are respectively bonded tothe first surface and second surface of the through type aluminum sheet;and secondarily pressurizing the first active material sheet and thesecond active material sheet simultaneously with second pressure higherthan the first pressure using a pair of second press rollers so that theprimarily pressurized first active material sheet and second activematerial sheet are connected through the plurality of first hollowprotrusion members and the plurality of second hollow protrusionmembers, wherein the first pressure is set by an interval between thepair of first press rollers, and the second pressure is set by aninterval between the pair of second press rollers.
 16. The method ofclaim 15, wherein in secondarily pressurizing the first active materialsheet and the second active material sheet, the second pressure isapplied so that thicknesses of the first active material sheet and thesecond active material sheet bonded to the first surface and secondsurface of the through type aluminum sheet are 2 to 30% smaller thanthicknesses of the first active material sheet and the second activematerial sheet bonded to the first surface and second surface of thethrough type aluminum sheet by the first pressure.